2.КОД:

/* Programma v zanannoi matritse menyaet zadannye stroki,

zatem iz poluchennoi matritsy poluchet treugolnuyi,

zatem vychislyaet summu polozhitelnyh elementov pod glavnoi diagonalyu

n*n-razmernost matritsy, I1 i I2- stroki, kotorye nuzhno pomenyut, s-summa*/

#include <stdio.h>

#include <math.h>

#include <conio.h>

void main()

{

float a[30][30], b[30][30], c[30][30],s;

int i, j, I1, I2, n;

printf("\n Razmernost matritsy n*n  \n Vvedite n:");

scanf("%d",&n);

{printf("\n Vvedite matritsu A:\n");

for(i=1;i<=n;i++)