关于数转字符以及5*5二维数组找最大

1、

#include<stdio.h>
#include<string.h>
/*
char *itoa(int a){
   static char b[20];
    int i=0,l;
    char t;
    while(a!=0){
        b[i]='0'+a%10;
        a=a/10;
        i++;
    }
    b[i]='\0';
    l=strlen(b);
    for(i=0;i<l/2;i++){
        t=b[l-1];
        b[l-1]=b[i];
        b[i]=t;
        l--;
    }
    return b;
}
*/

int main(){
    char *itoc(int a,char str[]);
    int a;
    char str[11];
    char *b;
    printf("please input a number:");
    scanf("%d",&a);
    b = itoc(a,str);
    printf("%s\n",b);
    return 0;
}
char *itoc(int a,char str[]){
    char stack[10];
    int top;
    int i=0,x;
    top = -1;
    while(a!=0){
        x = a%10;
        top++;
        stack[top] = '0'+x;
        a = a/10;
    }
    while(top>-1){
        str[i]=stack[top];
        top--;
        i++;
    }
    str[i]='\0';
    return str;
}

2、

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define N 5
int main(){
    void maxn(int a[][5],int n,int *x,int *y,int *max);
    int a[N][N];
    int i,j;
    int x,y,max;
    srand((unsigned)time(NULL));
    for(i=0;i<N;i++){
        for(j=0;j<N;j++){
            a[i][j]=rand()%100;
            printf("%4d",a[i][j]);
        }
        printf("\n");
    }
    maxn(a,N,&x,&y,&max);
    printf("max=%d,x=%d,y=%d\n",max,x,y);

    return 0;
}
void maxn(int a[][5],int n,int *x,int *y,int *max){
    int i,j;
    *max=a[0][0];
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            if(*max<a[i][j]){
                *max=a[i][j];
                *x=i+1;
                *y=j+1;
            }
        }
    }
}