View input and sum rows and columns

Hi, I need to fix a program with a main menu that prints the input inserted, sums the rows and sums the columns.
I made something up but it doesn't work and I can't understand why.

Here are the problems:
The function 2 prints random numbers in a loop.
The function 3 doesn't print anything
The function 4 prints just "0".

Code:

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#include<stdio.h>
#include<string.h>
int main(void)
{
  int selection;
  int matrice[30][30];
  int i;
  int j;
  int m;
  int n;
  int MAXn;
  int vet;
 
  do {
    printf
        ("+----------------------------------------------------------------------------------------------+\n");
    printf("1) input \n");
    printf("2) view input \n3) sum rows\n4) sum colums \n9) exit\n--->");
    scanf("%d", &selection);
    if (selection == 1) {
      printf("how many numbers will be inserted? ");
      scanf("%d", &n);
 
 
      printf("input a sequence of %d numbers\n", n);
      for (i = 0; i < n; i++) {
 
        for (j = 0; j < n; j++) {
          printf("element %d: ", i + 1);
          scanf("%d", &matrice[j]);
        }
        printf("\n");
      }
 
    }
    if (selection == 2) {
      printf("the sequence is the following:\n");
      for (i = 0; i < n; i++)
        for (j = 0; i < n; j++)
          printf("element %d: %d\n", i + 1, matrice[j]);
      printf("\n");
    }
    if (selection == 3) {
      int somma;
 
      for (i = 1; i <= n; i++) {
        int somma = 0;
        for (j = 1; i <= m; i++) {
          somma = somma + matrice[j];
          printf("sum: %d", &matrice[j]);
        }
        printf("sum: %d", somma);
      }
 
 
    }
 
    if (selection == 4) {
      int somma;
      int righe;
      int colonne;
      int a[10][10];
 
      for (righe = 0; righe < i; righe++) {
        somma = 0;
        for (colonne = 0; colonne < j; colonne++) {
          somma = somma + a[colonne][righe];
        }
        printf("The sum of Column Elements in a Matrix =  %d \n", somma);
      }
 
    }
 
    if (selection > 10)        // errore
    {
      printf("your choice is not valid");
    }
    if (selection == 9) {
      printf("Exiting...");
      getc;
    }
  }
  while (selection != 9);
 
 
 

}

---

Use meaningful variable names instead of i, m, and n.

Tim S.

There are many bad use of printf/scanf calls, and many unused or uninitialised variables.

Code:

---

$ gcc -Wall -Wextra -O2 foo.c
foo.c: In function ‘main’:
foo.c:30:17: warning: format ‘%d’ expects argument of type ‘int *’, but argument 2 has type ‘int (*)[30]’ [-Wformat=]
          scanf("%d", &matrice[j]);
                ^
foo.c:40:18: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘int *’ [-Wformat=]
          printf("element %d: %d\n", i + 1, matrice[j]);
                  ^
foo.c:49:17: warning: assignment makes integer from pointer without a cast [-Wint-conversion]
          somma = somma + matrice[j];
                ^
foo.c:50:18: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘int (*)[30]’ [-Wformat=]
          printf("sum: %d", &matrice[j]);
                  ^
foo.c:44:11: warning: unused variable ‘somma’ [-Wunused-variable]
      int somma;
          ^
foo.c:80:7: warning: statement with no effect [-Wunused-value]
      getc;
      ^
foo.c:12:7: warning: unused variable ‘vet’ [-Wunused-variable]
  int vet;
      ^
foo.c:11:7: warning: unused variable ‘MAXn’ [-Wunused-variable]
  int MAXn;
      ^
foo.c:19:5: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d", &selection);
    ^
foo.c:22:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
      scanf("%d", &n);
      ^
foo.c:30:11: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result]
          scanf("%d", &matrice[j]);
          ^
foo.c:48:9: warning: ‘m’ may be used uninitialized in this function [-Wmaybe-uninitialized]
        for (j = 1; i <= m; i++) {
        ^
foo.c:8:7: warning: ‘j’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  int j;
      ^
foo.c:7:7: warning: ‘i’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  int i;
      ^

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