Add double to string

include/utils/basic_functions.h

@@ -4,5 +4,6 @@
 double linear_interpolate(double *x_vector, long x_length, double *y_vector, long y_length, double x_value);
 char* concat(const char *s1, ...);
 void string_to_lowercase(char* str);
+char* to_str(double x);
 
 #endif //BASIC_FUNCTIONS_H

src/utils/basic_functions.c

@@ -42,4 +42,13 @@ char* concat(const char *s1, ...) {
 void string_to_lowercase(char* str) {
     char *p;
     for(p=str; *p; ++p) *p=tolower(*p);
+}
+
+char* to_str(double x) {
+    size_t l;
+    char *s;
+    l = (size_t)snprintf(NULL, 0, "%f", x) + 1;
+    s = (char*)malloc(l);
+    snprintf(s, l, "%.0f", x);
+    return s;
 }

tests/test_basic_functions.c

@@ -40,3 +40,10 @@ int test_interpolate(){
     TAIGA_ASSERT_ALMOST_EQ(15.4, y0, "decreasing order (case2)");
     return TAIGA_ASSERT_SUMMARY();
 }
+
+int test_to_string(){
+    TAIGA_INIT_TEST("TO STRING");
+    TAIGA_ASSERT_COMPARE("50", to_str(50), "exact value 50");
+    TAIGA_ASSERT_COMPARE("49", to_str(49.2), "rounded value 49.2");
+    return TAIGA_ASSERT_SUMMARY();
+}

tests/test_basic_functions.h

@@ -3,5 +3,6 @@
 
 int test_concat();
 int test_interpolate();
+int test_to_string();
 
 #endif //TEST_BASIC_FUNCTIONS_H

tests/tests.c

@@ -8,6 +8,7 @@
 int main(){
     return test_concat() +
     test_interpolate() +
+    test_to_string() +
     test_bspline() +
     test_solver();
 }