#include<stdio.h>                                
#include<math.h>                                
void main()                                
{
    double FD[10][20];        
double a[7][2];                                
int i,j;   

for(i=0;i<7;i++)                                
for(j=0;j<2;j++)                                
scanf("%lf",&a[i][j]);   

for(i=0;i<7;i++)
{
    if(a[i][1]==6)
    {
        FD[0][0]=a[i][0];
        break;
    }
    if(a[i][1]!=6)
    {
        FD[0][0]=0;
    }
}
                                            
printf("%lf \n",FD[0][0]);

}

double FD[10][20]; 假设有FD[0][0],FD[0][1],FD[0][2],FD[0][3],FD[0][4],FD[0][5],FD[0][6],......FD[0][19];
递归计算求值：FD[0][0]+FD[0][1]+FD[0][2]+FD[0][3]+......+FD[0][19];

#include <stdio.h>

int sum(int s[],int len)
{
    static int ret=0;
    if(len==0) return ret;
    ret+=s[len-1];
    sum(s,--len);
    return ret;
}

int main(int argc,char *argv[])
{
    int s[10]={1,3,5,7,9,11,13,15,17,19};
    int ret=sum(s,10);
    printf("sum=%d\n",ret);
    return 0;
} 

#include<stdio.h>
int SumUp(int**arr,int x1,int y1,int x2,int y2)//传入二维数组左上角及右下角元素下标
{
    if(y1<y2)
        return SumUp(arr,x1,y1,x2,(y1+y2)/2)+SumUp(arr,x1,(y1+y2)/2+1,x2,y2);
    else
        if(x1<x2)
            return SumUp(arr,x1,y1,(x1+x2)/2,y2)+SumUp(arr,(x1+x2)/2+1,y1,x2,y2);
        else
            return arr[y1][x1];
}
int main()
{
    int**arr;int x,y;//x,y保存数组规模
    int i,j;
    printf("请输入数组行数列数，以空格分开：");
    scanf("%d %d",&y,&x);            //自定义二维数组规模
    arr=(int**)malloc(sizeof(int*)*y);
    for(i=0;i<y;i++)
        arr[i]=(int*)malloc(sizeof(int)*x);//空间分配
    for(i=0;i<y;i++)
        for(j=0;j<x;j++)
            arr[i][j]=i*x+j+1;  //赋值,或据自己需要scanf赋值
    for(i=0;i<y;i++)
    {
        for(j=0;j<x;j++)
            printf("%d\t",arr[i][j]);//打印数组
        printf("\n");
    }
    printf("\n总和：%d",SumUp(arr,0,0,x-1,y-1));//求和
    for(i=0;i<y;i++)
        free(arr[i]);          //清理空间
    free(arr);
    return 0;
}