对C语言中不同类型数据计算速度的测试

我对C语言中各种数据类型的四则运算速度进行了测试。

操作系统：Windows 8.1 专业版 (64位)
编译器：GCC 4.8.1 64-bit Release (未开任何优化)
处理器：Intel Core i7-4702MQ

测试数据选择的都是12345和123

测试源程序：

#include<stdio.h>
#include<time.h>

#define test(expr){\
    printf("test: %s 100000000 times\n",#expr);\
    sum=0;\
    for(j=0;j<10;j++){\
        start=clock();\
        for(i=0;i<1000000;i++){\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
            expr;expr;expr;expr;expr;expr;expr;expr;expr;expr;\
        }\
        end=clock();\
        t=(double)(end-start)/CLOCKS_PER_SEC;\
        printf("%3d %.3fs",j+1,t);\
        if(j%5==4)printf("\n");\
        sum+=t;\
    }\
    printf("Avg %.3fs\n\n",sum/10);\
}

int main(){
    clock_t start,end;
    double t,sum;
    register int i,j;
    short short1=12345,short2=123,short3;
    long long1=12345,long2=123,long3;
    long long longlong1=12345,longlong2=123,longlong3;
    float float1=12345.0,float2=123.0,float3;
    double double1=12345.0,double2=123.0,double3;
    long double longdouble1=12345.0,longdouble2=123.0,longdouble3;

    test(NULL)
    test(short3=short1+short2)
    test(short3=short1-short2)
    test(short3=short1*short2)
    test(short3=short1/short2)
    test(short3=short1%short2)
    test(long3=long1+long2)
    test(long3=long1-long2)
    test(long3=long1*long2)
    test(long3=long1/long2)
    test(long3=long1%long2)
    test(longlong3=longlong1+longlong2)
    test(longlong3=longlong1-longlong2)
    test(longlong3=longlong1*longlong2)
    test(longlong3=longlong1/longlong2)
    test(longlong3=longlong1%longlong2)
    test(float3=float1+float2)
    test(float3=float1-float2)
    test(float3=float1*float2)
    test(float3=float1/float2)
    test(double3=double1+double2)
    test(double3=double1-double2)
    test(double3=double1*double2)
    test(double3=double1/double2)
    test(longdouble3=longdouble1+longdouble2)
    test(longdouble3=longdouble1-longdouble2)
    test(longdouble3=longdouble1*longdouble2)
    test(longdouble3=longdouble1/longdouble2)

    return 0;
}

程序输出：

test: NULL 100000000 times
1 0.000s 2 0.000s 3 0.000s 4 0.000s 5 0.000s
6 0.000s 7 0.000s 8 0.000s 9 0.000s 10 0.000s
Avg 0.000s

test: short3=short1+short2 100000000 times
1 0.031s 2 0.047s 3 0.031s 4 0.031s 5 0.047s
6 0.031s 7 0.032s 8 0.046s 9 0.032s 10 0.031s
Avg 0.036s

test: short3=short1-short2 100000000 times
1 0.047s 2 0.047s 3 0.047s 4 0.078s 5 0.047s
6 0.046s 7 0.063s 8 0.047s 9 0.047s 10 0.046s
Avg 0.052s

test: short3=short1*short2 100000000 times
1 0.032s 2 0.047s 3 0.031s 4 0.047s 5 0.047s
6 0.062s 7 0.031s 8 0.047s 9 0.032s 10 0.031s
Avg 0.041s

test: short3=short1/short2 100000000 times
1 0.328s 2 0.422s 3 0.297s 4 0.390s 5 0.282s
6 0.343s 7 0.297s 8 0.375s 9 0.360s 10 0.375s
Avg 0.347s

test: short3=short1%short2 100000000 times
1 0.390s 2 0.281s 3 0.344s 4 0.281s 5 0.297s
6 0.282s 7 0.296s 8 0.282s 9 0.359s 10 0.313s
Avg 0.313s

test: long3=long1+long2 100000000 times
1 0.031s 2 0.047s 3 0.031s 4 0.031s 5 0.063s
6 0.047s 7 0.031s 8 0.047s 9 0.031s 10 0.031s
Avg 0.039s

test: long3=long1-long2 100000000 times
1 0.063s 2 0.047s 3 0.046s 4 0.047s 5 0.047s
6 0.047s 7 0.047s 8 0.047s 9 0.047s 10 0.047s
Avg 0.048s

test: long3=long1*long2 100000000 times
1 0.031s 2 0.047s 3 0.031s 4 0.031s 5 0.047s
6 0.031s 7 0.032s 8 0.031s 9 0.047s 10 0.031s
Avg 0.036s

test: long3=long1/long2 100000000 times
1 0.281s 2 0.313s 3 0.343s 4 0.313s 5 0.266s
6 0.281s 7 0.344s 8 0.328s 9 0.312s 10 0.281s
Avg 0.306s

test: long3=long1%long2 100000000 times
1 0.313s 2 0.281s 3 0.282s 4 0.343s 5 0.297s
6 0.438s 7 0.328s 8 0.281s 9 0.344s 10 0.281s
Avg 0.319s

test: longlong3=longlong1+longlong2 100000000 times
1 0.031s 2 0.063s 3 0.047s 4 0.031s 5 0.047s
6 0.031s 7 0.031s 8 0.047s 9 0.031s 10 0.032s
Avg 0.039s

test: longlong3=longlong1-longlong2 100000000 times
1 0.093s 2 0.047s 3 0.047s 4 0.047s 5 0.063s
6 0.109s 7 0.078s 8 0.047s 9 0.047s 10 0.047s
Avg 0.063s

test: longlong3=longlong1*longlong2 100000000 times
1 0.062s 2 0.047s 3 0.031s 4 0.032s 5 0.046s
6 0.032s 7 0.031s 8 0.031s 9 0.031s 10 0.047s
Avg 0.039s

test: longlong3=longlong1/longlong2 100000000 times
1 0.985s 2 0.953s 3 0.984s 4 0.891s 5 0.969s
6 0.906s 7 0.953s 8 1.062s 9 0.876s 10 0.921s
Avg 0.950s

test: longlong3=longlong1%longlong2 100000000 times
1 0.907s 2 1.015s 3 0.922s 4 1.031s 5 1.079s
6 0.937s 7 0.875s 8 0.938s 9 1.015s 10 1.000s
Avg 0.972s

test: float3=float1+float2 100000000 times
1 0.047s 2 0.031s 3 0.032s 4 0.031s 5 0.047s
6 0.031s 7 0.031s 8 0.047s 9 0.031s 10 0.063s
Avg 0.039s

test: float3=float1-float2 100000000 times
1 0.047s 2 0.031s 3 0.031s 4 0.031s 5 0.047s
6 0.032s 7 0.031s 8 0.031s 9 0.047s 10 0.062s
Avg 0.039s

test: float3=float1*float2 100000000 times
1 0.032s 2 0.031s 3 0.047s 4 0.078s 5 0.031s
6 0.047s 7 0.031s 8 0.032s 9 0.031s 10 0.047s
Avg 0.041s

test: float3=float1/float2 100000000 times
1 0.265s 2 0.266s 3 0.250s 4 0.250s 5 0.234s
6 0.250s 7 0.266s 8 0.234s 9 0.250s 10 0.266s
Avg 0.253s

test: double3=double1+double2 100000000 times
1 0.047s 2 0.031s 3 0.031s 4 0.047s 5 0.032s
6 0.031s 7 0.031s 8 0.047s 9 0.031s 10 0.031s
Avg 0.036s

test: double3=double1-double2 100000000 times
1 0.047s 2 0.032s 3 0.031s 4 0.031s 5 0.047s
6 0.031s 7 0.031s 8 0.032s 9 0.047s 10 0.031s
Avg 0.036s

test: double3=double1*double2 100000000 times
1 0.031s 2 0.031s 3 0.047s 4 0.031s 5 0.032s
6 0.047s 7 0.031s 8 0.031s 9 0.047s 10 0.094s
Avg 0.042s

test: double3=double1/double2 100000000 times
1 0.547s 2 0.500s 3 0.531s 4 0.719s 5 0.484s
6 0.484s 7 0.500s 8 0.500s 9 0.485s 10 0.531s
Avg 0.528s

test: longdouble3=longdouble1+longdouble2 100000000 times
1 0.250s 2 0.250s 3 0.250s 4 0.234s 5 0.250s
6 0.360s 7 0.234s 8 0.250s 9 0.328s 10 0.250s
Avg 0.266s

test: longdouble3=longdouble1-longdouble2 100000000 times
1 0.297s 2 0.250s 3 0.313s 4 0.234s 5 0.281s
6 0.250s 7 0.313s 8 0.265s 9 0.250s 10 0.282s
Avg 0.273s

test: longdouble3=longdouble1*longdouble2 100000000 times
1 0.250s 2 0.328s 3 0.281s 4 0.297s 5 0.281s
6 0.281s 7 0.266s 8 0.297s 9 0.281s 10 0.235s
Avg 0.280s

test: longdouble3=longdouble1/longdouble2 100000000 times
1 0.640s 2 0.735s 3 0.625s 4 0.640s 5 0.672s
6 0.625s 7 0.641s 8 0.656s 9 0.656s 10 0.688s
Avg 0.658s

较为直观的统计表格（时间单位：毫秒）：

	sizeof	+	–	*	/	%
short	2	36	52	41	347	313
long	4	39	48	36	306	319
long long	8	39	63	39	950	972
float	4	39	39	41	253
double	8	36	36	42	528
long double	16	266	273	280	658

结论：

short并不一定比long更快，如果不是空间上的限制，直接选用long就可以。

long long在除法和取余运算上显著慢于long。

double只有在除法上才显著慢于float。

long double各种运算都比double慢。

浮点数计算(float、double)和整数计算(short、long)的速度不相上下。